Oscillator Electrical Specifications; 32.768-Khz Oscillator Specifications; Standard Input, Output, And I/O Pin Ac Operating Conditions - Intel PXA255 Datasheet

Electrical Specifications
Table 12. Standard Input, Output, and I/O Pin AC Operating Conditions
Symbol
CIN
COUT_H
tdF_H
tdR_H
1
NOTE:
4.6

Oscillator Electrical Specifications

The processor contains two oscillators, each for a specific crystal: a 32.768-kHz oscillator and a
3.6864-MHz oscillator. When choosing a crystal, match the crystal parameters as closely as
possible.
4.6.1

32.768-kHz Oscillator Specifications

The 32.768-kHz oscillator is connected between the TXTAL (amplifier input) and TEXTAL
(amplified output).
specifications.
Table 13. 32.768-kHz Oscillator Specifications
Symbol
Crystal Specifications - Typical is FOX NC38
F
XT
ESR
P
Amplifier Specifications
VIH_X
VIL_X
IIN_XT
CIN_XT
tS_XT
Board Specifications
RP_XT
CP_XT
COP_XT
28
Description
Input capacitance, all standard input and
IO pins
Output capacitance, all standard high-
strength output and IO pins
Output de-rating, falling edge on all
standard, high-strength output and I/O
pins, from 50pF load.
Output de-rating, rising edge on all
standard, high-strength output and I/O
pins, from 50pF load.
AC specifications guaranteed for loads in this range. All testing is done at 50pF
Table 13, "32.768-kHz Oscillator Specifications"
Description
Crystal Frequency, TXTAL/TEXTAL
Equivalent series resistance, TXTAL/TEXTAL
Drive Level
Input High Voltage, TXTAL
Input Low Voltage, TXTAL
Input Leakage, TXTAL
Input Capacitance, TXTAL/TEXTAL
Stabilization Time
Parasitic Resistance, TXTAL/TEXTAL to any node
Parasitic Capacitance, TXTAL/TEXTAL, total
Parasitic Shunt Capacitance, TXTAL to TEXTAL
Intel® PXA255 Processor Electrical, Mechanical, and Thermal Specification
Min Typical Max
1
25 50
shows the 32.768-kHz
Min Typical
— 32.768
6 —
— —
0.8*VCC
VSS 0.2*VCC
18
2 -
20
Units
10 pF
1
pF
ns/pF
ns/pF
Max Units
— kHz
65 kΩ
1 uW
VCC V
V
1 µA
25 pF
10 s
MΩ
5 pF
0.4 pF